boost/preprocessor/seq/detail/is_empty.hpp

   1 # /* **************************************************************************
   2 #  *                                                                          *
   3 #  *     (C) Copyright Edward Diener 2015.
   4 #  *     Distributed under the Boost Software License, Version 1.0. (See
   5 #  *     accompanying file LICENSE_1_0.txt or copy at
   6 #  *     http://www.boost.org/LICENSE_1_0.txt)
   7 #  *                                                                          *
   8 #  ************************************************************************** */
   9 #
  10 # /* See http://www.boost.org for most recent version. */
  11 #
  12 # ifndef BOOST_PREPROCESSOR_SEQ_DETAIL_IS_EMPTY_HPP
  13 # define BOOST_PREPROCESSOR_SEQ_DETAIL_IS_EMPTY_HPP
  14 #
  15 # include <boost/preprocessor/config/config.hpp>
  16 # include <boost/preprocessor/arithmetic/dec.hpp>
  17 # include <boost/preprocessor/logical/bool.hpp>
  18 # include <boost/preprocessor/logical/compl.hpp>
  19 # include <boost/preprocessor/seq/size.hpp>
  20 #
  21 /* An empty seq is one that is just BOOST_PP_SEQ_NIL */
  22 #
  23 # define BOOST_PP_SEQ_DETAIL_IS_EMPTY(seq) \
  24     BOOST_PP_COMPL \
  25         ( \
  26         BOOST_PP_SEQ_DETAIL_IS_NOT_EMPTY(seq) \
  27         ) \
  28 /**/
  29 #
  30 # define BOOST_PP_SEQ_DETAIL_IS_EMPTY_SIZE(size) \
  31     BOOST_PP_COMPL \
  32         ( \
  33         BOOST_PP_SEQ_DETAIL_IS_NOT_EMPTY_SIZE(size) \
  34         ) \
  35 /**/
  36 #
  37 # define BOOST_PP_SEQ_DETAIL_IS_NOT_EMPTY(seq) \
  38     BOOST_PP_SEQ_DETAIL_IS_NOT_EMPTY_SIZE(BOOST_PP_SEQ_DETAIL_EMPTY_SIZE(seq)) \
  39 /**/
  40 #
  41 # define BOOST_PP_SEQ_DETAIL_IS_NOT_EMPTY_SIZE(size) \
  42     BOOST_PP_BOOL(size) \
  43 /**/
  44 #
  45 # define BOOST_PP_SEQ_DETAIL_EMPTY_SIZE(seq) \
  46     BOOST_PP_DEC(BOOST_PP_SEQ_SIZE(seq (nil))) \
  47 /**/
  48 #
  49 # endif